Maeve, Mab, Titania, Aurora, Leanansidhe

[surarrin]

What type of fae are their base? Sidhe aside.

[Papa Gruff]

um ... perhaps I don't get the question ... but aren't they just fay/fairies? To me they have no underlining type or base.  They are Winter or Summer ... don't have to be something different in my opinion...

[Deadmanwalking]

Yeah, the types are basically a convenient shorthand. And the Queens are their very own sort of creature, different from all others.

[surarrin]

Alright, putting the Queens aside, how about Leansidhe

What I meant by Sidhe aside was;

Sidhe
Among the faerie, Sidhe is a state of being that
is somewhat political and somewhat biological.
A Sidhe has all of the abilities of its faerie type,
raised to greater heights of power. The Sidhe are
the aristocracy of Faerie, and that mindset must
be considered when dealing with them, regardless
of which Court—or no Court—they are
associated with.

[Papa Gruff]

Alright, putting the Queens aside, how about Leansidhe?

What I meant by Sidhe aside was;

The Leansidhe is just the same as the queens, only slightly less powerful.

[Deadmanwalking]

Leannan Sidhe IS it's own type of Fae. It's never referred to as an individual any where I've seen outside the Dresden Files, but as an entire type...now what that means for Lea is a bit unclear (is she the last of her kind? Or just the most powerful? Does she have a name of her own, that she conceals from Harry for her own reasons? etc.) but that's actually description enough in terms of creature type.

[surarrin]

“Such anger. Such fire. Yes. I watched you stalemate your godmother the Leanansidhe autumn last. Few mortals ever have done as much. Bold. Impertinent. I admire that kind of strength, wizard. I need that kind of strength.”

I figured it was her 'title' since it's always preceded by the.

[Deadmanwalking]

Oh, it is. Hence my speculation that she's either the leader of her folk (like calling a clan leader "The McCleod") or the last of her kind. 

[neko128]

Well, in Celtic folklore the Leanan Sidhe was a female who took a mortal lover.  It came from Leannan ("a sweetheart, lover, or concubine") and Sidhe ("of the fairy mounds").  In other myths (Irish, Scottish) she was also considered a muse - trading inspiration and talent to artists for their love and devotion - and had close ties to the concept of a succubus.

Take that and compare it to her actions, attitudes, and promises in the books.    It's not hard to go from the basic historical/mythological concept to when he made the deal with her, promising her devotion for life in return for inspiration in how to get out of the situation he was in.